3. Heuchera richardsonii R. Br. (prairie alum root)

H. richardsonii var. affinis Rosend., Butters & Lakela

H. richardsonii var. grayana Rosend., Butters & Lakela

Pl. 558 h; Map 2596

Petioles usually densely pubescent with relatively long spreading hairs having minute glandular tips, usually also with moderate to dense minute glandular hairs. Leaf blades 1.5–9.5 cm long, circular to broadly ovate, the upper surface glabrous or sparsely hairy, the undersurface sparsely to densely hairy, the lobes more or less rounded, the margins scalloped or toothed. Inflorescences 25–100 cm long, erect or ascending, the axes glabrous or sparsely to densely hairy with mostly spreading hairs to 5 mm long having minute glandular tips, also with scattered minute glandular hairs, especially on the branches and toward the inflorescence tip. Hypanthium at flowering 5–11 mm long, 4–8 mm in diameter, the free portion 2–7 mm long, conspicuously zygomorphic, broadly bell-shaped when fresh, minutely glandular on the outer surface, green to yellowish green, sometimes reddish-tinged. Sepals 1.5–4.0 mm long, minutely glandular on the outer surface and margins, the sinuses between the sepals relatively broad. Petals 1.5–4.0 mm long, oblanceolate to narrowly spatulate, usually minutely glandular on the outer surface and margins, green or white, sometimes pinkish-tinged. Fruits with the body 7.0–14.5 mm long, tapered into the 3.0–4.5 mm long styles. Seeds 0.6–0.9 mm long, ovoid, the surface with fine tubercles or spines. 2n=14, 28. April–June.

Scattered nearly throughout the state, most abundant in the Glaciated Plains and Unglaciated Plains Divisions, apparently absent from the Mississippi Lowlands (Michigan to Montana south to Indiana, Oklahoma, and Colorado; Canada). Upland prairies, glades, ledges and tops of bluffs, and rock outcrops in mesic to dry upland forests; also roadsides and railroads.